Grinding machine



Sept. 12, 1933. H WE|NLAND 1,926,471

GRINDING MACHINE Filed July 28. 1932 4 Sheets-Sheet l INVENTOH L l l I ATTORNEYS Sept. 12, 1933. H. G. WEINLAND GRINDING MACHINE Filed July 28. 1932 4 Sheets-Sheet 2- INVENTOR ATTORNEYS Sept. 12, 1933. H. G. WEINLAND GRINDING MACHINE 4 Sheets-Sheet 3.

Filed July 28. 1932 ATTORNEYS Sept. 12, 1933.

H. G WEINLAND GRINDING MACHINE Filed July 28. 1932 4 Sheets-Sheet 4 INVENTOR ATTORNEYS 'cludes Patented Sept. 12, 1933 UNITED sm'res 1,926,471 V GRINDING MACHINE Hermon G. Weinland, Springfield, Ohio, assignor to The Safety Grinding Wheel & Machine Company, Springfield, Ohio, a"corporation of Ohio npplicationJuly 28, 1932. Serial No. 625,256

14 Claims. ('01. 51-122) This invention relates to improvements in grinding machines'it more particularly relating to a machine of the type which has a reciprocating work table and a tool holder which isintermittently fed to the work.

One of the objects of the invention is to provide means controlled by thefeeding' movement of the 'tool holder for automatically changing the speed 'of-the table after apredetermined movement of the tool holder.

Another object of the invention is to provide means controlled by the feeding movement of the tool holder for automatically causing the work table to move from workingposition tounloading position. 7

Another object of the invention is theprovision of a fluid operated control mechanism controlled by the feeding movement of the tool holderfor changing thespeedof the Work table after a predetermined movement of the. tool holder; a further object in this connection being 'also to the work table to be placed in loading position after a further predetermined movement of the tool holder;

"Other objects will appear-from the accompanying description and statement of advantages. 1 In the accompanying drawings: Fig. l is an "end elevation of a grinding machine embodying the improvements. lg. 2 is a partial front elevation on a larger scale of the machine. v Y

' Fig. 3 isa fragmentary front larger scale, partly in vertical section, oifapor- Fig-.8 is a fragmentary side elevation on a larger:

scale, partly in transverse section, of 'a portion of the fluid operated feeding mechanism; and in-. a partial side elevation of one of the tool heads with thecover ofgthe casing removed.

Fig. 91s a view partly in horizontal section and partly in plan, the sectional portion being taken on the line 9 9 of Fig. 8. I T I "Fig. 1G is a fragmentary transverse section partly in elevation on a slightly enlarged scale on the line l010 of Fig. 8.- h Y of. the parts employed in the Fig. 11 is a. horizontal section on the line "11-11 of FigLlO. Y

Fig. 12 is a diagrammatic view in perspective showing on a slightly increased scale as compared to Fig. 1 the relation and interconnection fluid operatedcontrolling mechanism. a

Fig. 13 is an elevation partly in longitudinal section of a detail used in connectionrwith the control mechanism. 1

"Fig. 14 is also 1 an elevation, partly in tudinal section, of a detail,

in the machine of'thisapplication the work table is. given a reciprocatory movement by a longi-i rotary reversible fluidmotor which'is'reversed by the contact of dogs on the work .table with suitable tripping mechanism which controls .a

fluid operated reversing valve for the motor; The tool holder is advanced or fed toward the work in successive intermittent movements, a feeding fmovement occurring-at each reversal of the work provide fluid operated mechanism controlled by the feeding movement of'the toolholder to cause tablej'and ithe 'tool. holder is. retracted to. an initial starting point by .fluid operated means controlled by the work tablewhen the work table "reaches the unloading position. Provision is made forreciprocati-ng the work table at a given speed to impart to the work a series ofv roughing cuts and thereafter automatically reciprocating the work table at a reduced speedto impart to. the work a series ofyfinishing cuts, this change in speed being'under the control .of the tool holder" feeding mechanism. Provision is also i a, made for automatically causing the work table to elevation on a i move to unloading positionaftera predetermined number of finishing cuts have been imparted to the work, this latter movement of the table being also-under the control of ,thetool holder'feeding mechanism.. 1 j.' a

Referring tothe drawings, 1 represents a bed on the upper surface oi-which is slidably mounted atable or .work holder 2' on a V -way 3 anda flat way 4i.

compressed air, and the motor a'rotary; compressed air motor mounted at the rear and at the right end of the base 1'. The motive power is transmitted to the workholder. 2 through atrain of gearing (Figure 2) there being a pinion '7 secured to the shaft 6of the fluid 11101301.:5'1116511- ing with an idler gear 8,a pinion'9 secured thereto, a second idler gear 101 with which the idler pinion 9.m eshes and a pinion-11 secured to. the idler gear 10. The pinion '11- meshes with a master gear. 12 which also is in mesh with a Motion is impartedto the work .holder bya reversible'rotary fluid motor 5 (Figs, -1 and 2)., the fluid in the present case being.

rack 13 affixed to the under side of the work holder 2. I

A grinding element is indicated at 14. This is a ring type wheel, the grinding operation being' performed by applying the face of the ring to,

the work. The grinding wheel 1e is supported in a cup-shaped chuck 15 which is secured at the forward end of a spindle 16 rotatably'mounted in 'a tool holder or head 1'7 slidably'mountedon the upper surface of a lateral extension l8ofthe base 1. An electric motor 19 is mounted on the tool head 1'7 and transmits its power to the spindle 16 by means of a pluralityof V-belts 20 passing over a grooved pulley 21 on the rnotor' shaft and over a grooved pulley 22 on the-wheel spindle 16.

In the present machine the work holder move ment is reversed by actuation of a pilot valve which controls a fluid motor, operating the reversible valve'of the work holder rotary motor by contact of adjustably positioned pivotal stop dogs .24 and 25 secured on the forward vertical edge of the work holder cooperating with a pair of trip levers. One of the stop dogs, such as the dog 24 (Figs. '1 to, 5 inclusive) makes contact with one lever 26 of a pair of' trip levers 26 and 27,

- each of which is keyed by'a key 27,.(Fig. 7) to the reduced diameter outer extension of a short hollow horizontally disposed rock shaft 23. Each trip lever is placed side by sideron the shaft 28, and the stop dog 25 is sufficiently offset with ref- 1 erence to the dog 24 so as to make contact only with the mating lever 27. Each trip 'lever is forced through aportion of its swing by the direct contact of the stop dog, while the remaining portion is accomplished by a well known camming device, a boss I) on the trip lever 27.riding under the point of a resiliently supported wedge shaped block b. This block acts as a cam to quickly complete the shift of the pilot valve and thereby eliminates the possibility of a failure of the work holder to'reversedue to a stoppage of the piston-valve at its mid-stroke; If there is any tendency of-the work-holder to overrun, the stop dog merely passes over the upper end of its respective trip lever. Therefore, when each'dog in turn strikes its respective trip lever, the fluid *motor 5 is reversed through mechanism now to be described and the direction of the work holder 2 is changed. I a s The rock shaft 28 which is hollow for a greater 7 portion of its length, there being an axial bore 28 therein extending from its inner end to near its outer end, is rotatably supported in-bosses 29 integrally attaohedto a cover plate30 (Figs. 3 and 4) secured to the forward wall of the base 1. The rock shaft 28 projects into the interior of the base 1', andon the inner end thereof is clamped a member 32 having a downwardly extending crank arm 33, the angular'position of which thereof with respect .to the trip levers may be readily altered, if desired, by jlooseningfthe member clamping bolt 35, with which per '32 is provided. r

the mem- Work-holder motor reversing devices Instead of mechanically connecting the trip levers with the reversing valve of thefluid motor 5, fluidpressure devices are employed, similar to the fluid. operated means shown in my co-pending U. S. application Serial No. 577,903. The.

i motor reversing valve 36' is housed in an extension 36 (Fig. 1) of the motor 5, and is provided with a downwardly extending lever 37 (Figs. 1 and 2). The reversing valve is rocked '42 by means of the circumferential centrally located groove 49 of the pilot valve 45, is in posi tion to supply fluid to the left end of the reversing cylinder 38 through the conduit 42. The

and through an exhaust port pose.

to and fro by a fluid motor having a cylinder 38,

a'piston 39 (Fig. 2) and a piston rod 40, the

.of which is pivotally connected by a link 47 to 'thelower end of the crank arm 33.

With a move- 25- strikes the trip lever 27 which is then in. a vertical position as shown by the dot dash lines (Fig. 3') and swings it to the left or to the full line position, which movement results in shifting the pilot valve to theopposite end of its travel.

The pilot valve 45, as-shown in full lines in 3, by diverting the fluid received through the supply conduit 48 (Figs. 3 and 12) to the conduit ment of the work holder 2 to the left, the dog Y movement of the piston 39'to the right rocksfthe from the right end of the cylinder 38 is permitted to-escape to atmosphere through the conduit 43 1 When the pilot valve 45 is forced to the-right .as; shown by the broken line in Fig. 3 by contact of the stop dog-25 and thetrip lever 2'7, the fluid received through the supply conduit 1 48 is cut off from the conduit 42 andis diverted to the conduit 43 leading to the right end of the reversing cylinder 38, forcing the piston 39 therein to the left, thereby reversing the direction of the work holder. The fluid displaced from the left end of the cylinder 38 flows through the conduit 42' and escapes to atmosphere through a plurality of ports 51 ingthe pilot valve 45 and through the port 50 as described-above.-

The trip lever 26 is slidably mounted on the rock shaft 28, the key 2'7 serving as a spline, whereby the trip lever may be moved from its normal'position. for a purpose which will appear later. The normal position of the trip leverr 26 is such that it will be struck bythe stop dog 24 and is retained in normal position by the pressure of a coiled spring 52, one end of which bears against the hub 53 (Figs. 4 and 5) of thelever 26, the otherend bearing againsta disk 54 secured at the outer'extended end of the rock shaft 28, there being a flat head screw 56'threadedinto the solid end of the rock'shaft 28 for this pur- TooZ-head positioning and feeding" i The tool head 17 is preliminarily positioned ;a predetermined distance'from the workby manual'rotation of a lead screw 57 (Figs. 8 and 8), as for example, so that the face of the wheel is one-eighth inch therefrom, in order to allow a piece of work inthe rough to pass the wheel. At each reversal of the work holder, the tool head 1'7 is fed towards the work a predetermined distance by a fluid operated feeding mechanism also J.LJO similar in principle to the feeding mechanism reversing valve toia position by which the motor 5-is caused to run in a direction whereby the work holder will be moved to the left. During .this movement of the pilot valve, fluid displaced to the loading position.

, 1,926,471 shown and described in my co -pending U."S applicationSerial No. 577,903, and again described indetail herein in order to explain the action of additional fluid controlling devices employed is returned cured to the side of the tool head 17. A ratchet disk 59 is rotatably mounted on a horizontally disposed stud 60 projecting forwardly from the rear wall of the casing 58, and which is provided tion of its extended length;

.with an axial bore 60' (Fig. 9) for the greater por- The ratchet'disk is intermittently actuated to cause: successive partial rotation in one direction by the engagement of a pair of springpressed pawls, 61 and 62, (Fig. 8) one each being positioned in the outer end of each of a pairof diametrically opposed levers 63 and 64 (Figs. 8' and 9), the pawl 61beingso turned that a downward movement of the lever 63 engages the ratchet teeth and results in a partialrotation in an anti-clockwise direction, while the'pawl 62 is so placed in the lever 64 that an upward movement of the lever 64 continues theanti-clockwise partialrotation of the ratchet disk 59. The lever 63 is pivotally mounted on a stud 65, and its the tool head. 1'7 is mating lever 64 is also pivotally mounted on a stud 66. Both the studs 65 and 66 are fixed in a member 67 secured in the present case a cross-pin to the outer end of the hollow stud 60; Each lever 63 and 64 is interconnected at its. adjacent end by a link 68 so that motion from one causes a similar movement in the other.

upwardly and downwardly by means of a small fluid motor, the cylinder of which is represented the lever 63, and thecylinder 69 is pivotally supported at its lower end to the inside lower portion of the casing 58 to allow for the arcuatemovement of the cylinder due to the direct connection of the piston with the lever 63. Ateach re- H t motion from the ratchet disk 59 through a trio versal of the work holder 2, ;fiuid pressure is'delivered at each end alternately of the cylinder 69 through conduits '72 and73 (Figs. 2, 3 and 12) from the cylinder 44 under the control of the pilot valve 45, and through means to be described wards the work.

versal is governed by varying the distance through which the levers 63 and 64 swing, fr oin a full swing, where several ratchet teeth are engaged and aflmovement of several one-thou- 'sanclth parts of aninchresults, to a swing where one tooth only is engaged and the minimum members, one jaw '74 being interiorly threaded" with a right-hand thread while the jaw 74 is provided witha left-hand thread: (Fig.8) Both jaws are threaded on a 'vertically disposed ,threaded rod 75 rotatably supportedin bearings integrally attached to the member 67 and each jaw projects outwardly so that the upper jaw 74 extends over, and the lower jaw '74 extends be-' i 1 V increased. i The mechanism by which the intermittent feedf ing is accomplished is housed in a casing 58 serial No. 577,903. The-segment arm 76-is keyed" r'atch'et disk 59 andthe pinion 86. Pressureis moved intermittently tot coiled spring (Fig; 9)"to provide suffic'i'ent irie- The distance the tool head moves'at each re- 1 It has been stated that the grinding operations apart by rotating the rod 75 in the other direction, the possibleswing andtooth engagement .is increased, andthe amount of feed per reversal is In'tne present'machine, the fluidjoperatedttool feeding devices employ a segment arm, a pinion V and a rack in the same manner as described in the aforementioned co-pending application Seto ahorizontal'shaft 77 (Figs. 8 and 9) carried in.

bearings 78, one offwhich isindicated in Fig. 9.

Near thecenter," the shaft 'l 7' is provided with a pinion 79 which meshes with a-short r'a'cki80. I The teeth of the rack 80 are milled'in'an integral extension of a nut 8l through which the lead. screw-57 is threaded. The *nut 81 is slidably mounted on the under. side of the tool head-l7 and retained imposition-by gibsj82- (Fig. 8). se-

' cured to the tool head. Therefore, when the seg- 00 ment arm 76 is'movedin either'direction there- 7 ployed in connectionwith the tool feeding mechanism is for the purpose of permittingthe use of 5110 a small fluid motor to actuate the levers-63 and 64, as, with the small'motor, forward motion of the tool hea'd'maybe "arrested at'any desired point'by allowingjthe segment arm 76 to come [The levers 63 and 64 are alternately moved' 76 gear. teeth are cut, with which the teeth of 24 pinion 83 are meshed. .The=pinion 83 is secured to a gear, 84which; is rotatably mounted on a stud 85' secured to the rearwall of the casing 58. A freely'rota table pinion66 carried on the-hollow stud '60' meshes with'the gear 84;"and receives its tional arrangement. consisting of -a fiber plate 87 interposed between the d is1 s 88 and89' integrally attached r'espectively to {the .rear side or" the,

maintained on the fiber plate by means of'a tion to drive the'partslthe spring being placed in a counter bore in" the hub of the ratchet disk 59 .and encircling the hollow Stud 60 at that" point, and bearing againstthe member-67; The purposeof the frictional arrangement will appear Work-holder speed change consist of roughing andvfinis hing grinding cuts, the roughing cuts being taken at 'acertainwork holder speed while the finishing cutsare performed at a lower rate. Provision by-whichthe 1 work holder speed is alteredfautomatically,'al-

lowing byadjustment a'predetermine'd number of roughing cuts to be made", followed by a predetermined number of finishing cuts at the lower speed will nowbe explained. r 1 1 r a During-the rough grinding operations, the segment ,arm '76 descends intermittently, and in the path, of this arm is the free end of a lever 91 (Fig.

10) pivotally connected-at its other end to one end of a-valve casing 93, which lever when-depressed by the segment arm openssuccessively two valves.- The first of these valves to open is shown at 92 (Figs. 10 and 11). Thisvalve is caused to be.

or later period with reference to the time of contact of thesegment armj76 with the lever 91,

there being an adjusting screw 94 threaded into M and so'located inrthe lever 9,1- as to bear against the upper end of the stem-92 of the valve 92."

, When the valve 92 opens, fluid is passed from the supply conduit 96 (Figs. 3, 11 and 12) to a conduit 97 leading from the casing 93 to the cylinder 98 (Fig. 13) of a fluid-operated throttle valve interposed in the mainsupply conduit 99 leading tothe rotary motor 5 (Figs. 1, 2 and 12) wherebya piston 100 '(Fig. 13) in the throttle valve cylinder is forced downwardly. The piston 100 has apiston rod 101, at whose lower 6116.13

' is provided with a plurality of openings, the size 1 fixed'a valve 102 of the poppetptype, and the, downward movement of the piston 100 causes the valve 102 to be seated .on its seat in the valve-body 103. The diskportion of the valve 102, however,

and number of which insure that sufiicien tfluid is passed therethrough to operate thework holder at the desired lower speed; i

v Work holder return toloiadirtg pos ition For each subsequent reversal of the work holder.

the segment arm '76 further depresses the lever 91.

This further movement eventually opens the second valve 105 similarly housed in the casing 93,

' the valve 105 being actuated by contact of an adthe contacting ends of the valve. stem and screw thereby allowing a certain number ofifinishing. V

' the trip lever 118. Arod 128. (Fig. 3)]is pivotally connected at one end to the inner side of the cuts to be made. I I

When the valve 105 is allowed to flow from the supply-conduit 96 through a short port 109, and after-passingthe valve 105 through a conduit 110 (Figs. 9 and 12) to theinterior of the rock shaft 28 (Figs. 4'and 5) previously mentioned. It was previously statedthat 26 to be'moved'outwardly against the compression of the spring 52, for thepurpose of allowing the stop dog 24 to pass by the trip lever26 on a movement of the work holder to the right and to continue in that direction to the loading positio where the finished work is removed. I

111 in the bore of the rock shaft 28. Uponadmission of fluid pressure to the bore of the shaft 28,

the piston lllmoves outwardly andbearsagainst a cross-pin.112, which is loosely fitted through axial slotted openings 113 (Figs. 4, 5 and 6) in the rock shaft 28. The' projecting ends of the cross pin 112 bear against the recessed hub'jll l of the opened fluid pressure is circumferential wall 115 obtained in forming the is conducted to, the interior of the shaft 28'. Referring to Fig. 4 in which the normal position of the trip lever-26 is shown, it will be seen that the dog 24 will strike thetrip lever .26 and cause a reversal of the work holder as described. In

trip-clever 26, the cross pin being retained by-lthe Fig. 5, however, thetrip lever 26is shown as hav-" ing been moved out of the pathof the dog 24 and' therefore no contact resulting in reversal is made and the workholder continues to moveto the right.

The continued movement of the work holder 2 1 to the right when the trip lever 26 is thrown out of contacting positionis arrested at the right end of the bed 1, at the loading position, by the, contact ofthe stop dog 24 with a trip lever 118, which whenswungtothe dot dash position as seen in Fig. .3, causesthe closing, through linkagetobe described, of a dual purpose valve 119 enclosed in a valve body 120,(Figs. 1, 2, 12 and I l) V This valve 119 is interposed in the main fluidsupplyfconduit 99 and the conduit 99' leading to the rotaryfiuid motor ,5, and ;when closed, the 'fluidlto the motor 5 is shut offand the work holder 2 comes to a stop.

The. valve 119 is actuated through linkage as 1 The trip lever 118 is attachedto ashaft 121 which is rotatably mountedin a boss 123 (Fig.3) in the forward side. of the base 1. On the inner end of the shaft 121, a'cranle arm 124 is securedat whose lower endis pivotally connected alinkl25, the opposite end of which is pivotally connected to the upper, end of a lever 126 secured to the stem of the valve 119 (Fig.

14) The shaft 121 has also attached thereto a hand lever 127, which moves to the depressed position shown in broken. lines when the valve 119 is closed. As the motor 5 was stopped when the work holder can move only to the left when the valve 119 is again opened, and to also place the trip lever 2'1 inoperative position. This is accomplished by linking-the rock shaft 28 with Jrunning in a direction whereby the work holder triplever 26. The other end of the rod is passed of the rod 128 adjustably fixed by a set'screw,

a collar 130; atjsuch distance from the swivel" block 129 as to cause nointerfere'nce with the ordinary swingingmovements of thetrip levers 26 and 27 when the trip'lever 118 is in vertical position, in which position the valve 119 will be received from the valve-105 causes the trip lever open'.., The collar is, however, sufiiciently close" o theblock 129 as to insure that, when the 24 with the trip lever 118, the trip lever 27 will assume its vertical position asshown in dot dash lines in Fig. 3. This is accomplished by fitting a small piston work holder rotary motor 5 is also shifted. The

motor 5 can then start, when fluid. isagain admitted to it by raising the hand lever 127, only in the direction whereby the work holder is moved from theloading position and is thus prevented from running off the right hand end of the bed Further, the trip lever 27 is also brought into posi tion to limit and reverse the movement of the work holderto the left.

Retraction of tool head The closure .ofthe valve 119'also accomplishes purposes other than stopping the work holder,

in that the tool head 17 is retracted to its initial 1 point and incidentally portions of the feeding mechanism are restored to the starting position. The fluid pressure on the trip lever 26 is also relieved whereby the spring 52 returns the trip lever 26 to its normal position. Full speed operation of the work holder is also resumed when the valve 119 is again opened. l 7

Referring to Fig.'14 the valve 119 is shownin I its open position, the curved port 131 therein beingin communication with the conduits 99 and 99?. To shut off the fluid tothemotor 5 the valve 119 is rotatedin an anti-clockwise direction, the port 131 assuming the broken line position. I This position provides that a smallamount of fluid is admittedto a conduit 132 througha small port 133 in the body 120. The conduit 132 branchesinto the conduits 134 and 135, the conduit 134 leading to a fluid motor formed in the hollow shaft 60, andthe conduit 135'v to;a fluid motor 135 connected with the segment arm '76, both of whichjare parts of the feeding mechanism.

When the valve 119 is returned to the open position. shown in full line position in Fig. 14, the

- said motors are connected to atmosphere through rod 138, the'piston rod 138 beingpivotally connected to-the segment arm near the upper central pbrtion thereof, and fluid pressure isadmitted to the cylinder 136 below the'piston. Before the up-- ward movement of the segmentcan take place,

however, since the pawls 61 and 62 are at all times in engagement with the teeth of the ratchet disk 59, it is necessary that .the ratchet disk 59 be freed from its frictional engagement with the pinion- 86, whereby the-pinion 86 is allowed to rotate freely. The release of the'frictional engagement is made as follows: In the hollow shaft 60 a piston 139is fitted. This pistonbears against a crosspin 140 positioned in a manner similar to that described in connection with the 'trip lever 26. The cross pin 140 is loosely inserted in elon- "gated openings in the walls of the shaft 60, and

its projecting ends bear against the recessed hub of the ratchet disk 59. The movement is limited tobut a few thousandth parts of an inch, being merely sufficient to relieve the friction of the plate with the adjacent members. Thus when an application offluid pressure is made simultaneously the frictional engagement is broken, and the segment arm 76 is forced upwardlyJ As the arm '76 rises, the lever 91 follows it for a short distance in its upward movement and thervalves 92 and 105 are seated due to the combined pressure of a plurality of coiled springs, there'being a spring 149 belowthe valve 92, and a spring 150 be-. low the valve- 105. The seating of this valve 92 results in allowing the speed reducing valve 102 to rise and provide the full area fluid flow whereby the higher work holder speed isobtainable on 7 again starting the machine.

The fluid displaced by the rise of thepiston .100 is forced back through the conduit 97 into the bore 143 above the valve 92 and expelled to atmosphere by a ball-check valve 144 (Figs. 10and 11) there being a port 145 leading from the bore 143 above the seat of the valve 92 to the chamber 146 in which the ball 144 is seated. The ball is lightly held to its seat by a spring 147and a plunger 148, the spring 147 being interposed between the upper. end of the plunger and the lower side of a laterally extending ear 148' on the lever 91.

The seating of the valve 105 by the rise of the segment arm 76 results in shutting off thefluid by which pressure is exerted against the piston 111 (Figs. 4 and 5) whereby the spring 52 now re-' turns the trip lever 26 'to its normal position. The

expulsion of fluidfromthis motor is in a manner similar to that described for the speed reducing motor, the fluid being forced to return through the conduit 110 to the bore 151 above the seat of the valve 105, and thence to atmosphere, lifting a ball-check valve 151f (Fig. 11), there also being a port 151" leading from the borel51 to the chamber in which the ball 151 is seated. The ball 151' is also lightly-held to its seat in the same manner'as just described for the ball 144 and since the lever 91 normally rests on the springs by which. the balls are held down, the downward movement of the lever 91 increasesthe pressure on the balls and provides suflicient additional loading to prevent escape of fluid when the valves 92'and 105 are opened. s

' The upward movementof the segment arm '76 which causes the toolhead 17 to recede to its initially set'positionis arrested by contactof the arm with an adjustable stop screw 152 located in the sloping upper wall of the casing 58. Therefore, from the moment the segment arm YE-leaves the adjustable stop screw 152 to the time the arm depresses'the lever 91 sufliciently to open the valve 105," the tool head 17 is advancedtoward the work a in successively intermittent movements occurring at each reversal of the work holden'while' the receding movement of the tool head is made in one single movement. The swing is varied by turning the stop screwin or out,*resultingin a total head movement of a lesser or greater degree, as desired. 4

V Operation of machine 7 e In operationpthe work is placed on the work holder when this member is at, its loading position, i. e.,' at the right hand end ofthe bed 1. To

startfthe work holder, the handlever 127 (Figs.2 and 3) 'isswung upwardly to its horizontal position as shown in full lines. Through the linkage described, this movement results in placing the valve 119 (Fig. 14) in position tosupply fluid'to the rotary motor 5, and-the friction releasing fluid .motor in the shaft 60 and the segment arm motor 135. are permitted to exhaust to atmosphere. Inasmuch as the trip lever 26 had already returned to its normal position, work holder reversals will again be resumed automatically by the contact of the stop dogs 24 and 25 with the :trip levers 26 and'27, respectively. After the desired number of roughingstrokes have been made, the valve'92 is opened, resulting ina decrease in 1 the work holderspeed "to provide a slower speed for the finishing cuts, at the conclusion of which the valve 105is opened. The opening of the valve 105 results inrforcing the trip lever 26outqr .wardly from its normal position, andj'allow ithf 9 point at which the work isfflnished; If more of work holder to move to the right to loading position where the work holder is automatically stopped by closing the valve 119, and the work is removed. 'Ifheclosingmovementof the valve119 results in restoring the toolflhead to its initial position and incidentally allowing the speed reducing throttle to resume its fully opened position andto permit the trip 1ever26 to again assume.

allowing the grinding wheel to merely clear the,

rough surface of the workfand still advance to the the surface is to be removed, the tool head 17 I maybe moved toward the work by use of the lead screw, but it would likely be. advisable to run the stop screw 1521 outwardly in order to provide a greater moveme'nt whereby the rough surface may againbe cleared. I

- Having thus described my'in'vention, I claim: 1 In a grinding'machine, a work table, means for recipro cating the table, a tool holder, means to impart aieedingmovement to said holder, and means controlled'by'the feeding movement of said holder'to changethespeed of "said table after a predetermined movement of said holder.

2. In a grinding machinaa work tabla a 11101301 for moving said table, means controlled by the table to reverse the direction of said motor toimpart reciprocatoryomotion to saidtable, a tool holder, means for feedingsaid holder,and means controlled by the feeding movement of said holder fltolohangethe speed of said, motor after a predetermined movement of said holder. v v 3. In a grinding machine-a workitable, a fluid motor for reciprocatingthe same, a valve tocontrol the speed of said motor, a tool holder, means toimpart a feeding movement to said holder, and

means controlled by the feeding movement of. said holder to operate said valve to change thespeed of said table after a predetermined movement of said holder. a I a w 4. In a grinding machine, a work table, a fluid motor for reciprocating said table, a fluid operated valve to control the'speed of'said motor, a control valve to control the fluid whichoperates the fluid operated valve, a toolholder, means to impart a feeding movement to said h older, and

means controlled by the feeding movement of. said holder for operating said control valve to admit speed of said table afterapredetermined movement of said holder.

5. In a grinding machine, a work table, a fluid motor for ,reciprocatingsaid table, a normally open valve to supply fluid to said motor, said valve having" a reduced fluid admission port therethrough, a control valve to control the fluid which operates said first valve, a tool holder, means for imparting a feedingmovementto said holder, and means controlled by the feeding movement of said holder .to operate saidcontrol valve to admit'fiuid to operate said flrst men- "tioned valve to close the same to: thereby admit a reduced supply of fluid tosaidmotor to reduce 'the'speedthereoffl 1 .6. In a grinding machihe,1a work table, a fluid motor, means fluid to saidfluid operated valve to change the operated by the table to reverse" the direction of sai'd motonatool holder, feeding devices to impart a feeding movement to said holder, and means controlled by the. feeding -d e-' vices for said holder to change the speed of said table after a predetermined movement of said holder. I

'7. In a grinding machine, a work table, a fluid motor, means operatedby the table to reverse the direction of said motor, a tool holder, feeding devices 'to impart a' feeding movement to said holder, and-means controlled by the feeding devices for said holder to change the speed of said table after a predetermined movement of said holder, said means comprising a fluid operated valve to controlthe admission of fluid to said 8. In a grinding machine, a work table, a fluid motor, means operated by the table to reverse the direction of said motor, a tool holder, feeding devices to impart afeeding movement-to said holder, means controlled by the'feeding devices for said holder to change the speed of said table aftera predetermined movement of saidholder, said means comprising a fluid operated valve to control the admission of fluid to said motor and a second valve operated by said feeding devices to control the fluid which operates said first valve.

9. In a grinding machine, a work table, afluid motor forreciprocating said work table, means including a pair of trips to reverse the motor at the end of each reciprocatory movement of said table, a tool holder, means for feeding said holder, fluid operated means for throwing one of said trips outof operative position to-permit the motor to move the table to, loadingrposition, a valve controlling said fluid operated means,means for'operating said valve by the feeding movement .of said tool holder, a third trip to control the admission of fluid to said motor, and means on the table to operate said'third tripto cut off the fluid to said motorwhen the table has reached loading position.

10. In a grinding machine, a forreciprocating the tab1e, a tool holder, means to impart a feeding movement tov said holder, means controlled bythe feeding movement of the holder to change the speed of said table after.

by the table'to reverse the direction of said motor 'to impart reciprocatory motion to said table, a

tool holder, means for feeding said holder, means controlled by the feeding movement of said holder to change the speed of said motor-aftera predetermined movement of :saidholder, and

means operated by the feeding movement of said holder to render the motor reversing means inoperative after a predetermined movement of' said holder'topermit. the table to be moved to loading position.

12. In a grinding machine,

a work table, a

motor for moving said table, means controlled by the table to reversethe direction of said motor to impart reciprocatory motion tosaid table, a tool holder, means for feeding said holder, means controlled by the feeding movement of said holder to change'the' speed of said motor after a predetermined movement of, said, holder, means operated by the feeding movement of said holder to render the'motor reversing means inoperative work table, means ated by the table for reversing thedirection of said motor at the end of each reciprocatory movement of said table, a fluid operated valve to control the speed of said motor, a control valve to control the fluid which operates the fluid operated valve, a tool, holder, meansto impart a feeding movement to said holder, means controlled by the feeding movement of said holder for operating said control valve to admit fluid to said fluid operated valve to change the speed of said table after a predetermined movement of said holder, and a second control valve operated by the feeding movement of said holder to render theimotor reversing means inoperative to permit the motor to move the table to loading position.

14. In a grinding machine, a reciprocatory work table, a tool holder, feeding mechanism for said tool holder, said mechanism including pawls and an axially movable ratchet wheel, a gear normally engaged with said wheel, a fluid motor to move saidwheel axially, and fluid supply means for said motor controlled by said work table.

HERMON G. WEINLAND. 

